Some interesting numbers given. I was estimating around the $150 to $160 PD mark as well. We are 'eat at home' people most of the time. A big galley makes that easy. We also don't mind spending on a few high dollar excursions like a flightseeing tour or fishing charter.
The unforeseen can be the really big hits to expenses. Last time a crack was discovered in the frame which resulted in a rebuilding of all spring hanger mounts. This time the better part of $3000 will go into a full truck service & trailer brake service before we leave. I'm thinking something over $20,000 for a four month trip all in.